Control system



Oct. 14, 1941. RAYDEN comm SYSTEM Filed se i. 10, 1938 Inventor: Raymond G. fiayclen, y

His Attorney.

Patented Oct. 14, 1941 CONTROL SYSTEM Raymond G. Rayden, Rugby, England, assignor to General Electric Company, a corporation of New York Application September 1o,19ss, Serial No. 229,321

In Great Britain December 2, 1937 5 Claims. (Cl. 242-75) This invention relates to the control of electric motors and more particularly to the speed control of an electric motor driving a reel on which a length of material such as steel is being wound. An object of this invention is to provide means whereby the linear speed of the material being wound on the reel is kept approximately constant and also to provide means for presetting the linear speed of the material over a wide range.

ated brush gear.

to the speed of the material.

tion.

invention.

brush shifting gear I40, driven thereby.

closed. Contactor ll relay 22.

23 which will close and start the pilot motor 15 which operates the brush shifting gear of the reel motor, in a direction to increase the speed of the reel motor. When the linear speed of the materialreaches the preset value, relay 22 will pick up and drop out contactor 2| which in turn drops out raise contactor 23.

As soon as contactor 23 drops out, an energizing circuit for lower contactor 24 is completed through interlock contacts 221;; of relay 22 Although t invention i applicable t any and interlock contacts 23a of raise contactor type of variable speed c or t t 23. Contactor 24 picks up and connects brush will be described in connection with a variable Shifting Pilot moi/0r 5 to the source for rotation peed A commutator tor ith m to open in a direction to lower the speed of the commutator motor. Relay 22 is preferably designed to This invention consists in providing a tachomedrop out at a voltage Dp fie y 2% to 5% ter-generator driven in accordance with the s than s P p Veltage ue 0 that when speed of the strip by any suitable means such, for e linear Sp d Of the material has pp t0 example, as pinch rolls through which the matethis Value, CohllaCtOr 24 p rial passes before being wound on the reel so As the diameter of the coil of material builds that the voltage of the generator is proportional p on the e the linear sp wi l in ease un- The armature of til relay 22 picks up again and the operation dethe generator is connected through an adjustable scribed in the foregoing s repeated. In this way resistance to the contacts of a sensitive electrothe Speed of the reel motor is reduced in small responsive device and the resistance is set in ac- 25 Steps and the linear p e f mate ial remains cordance with the linear speed of the material approximately s ntat which it is desired that the electroresponsive T0 Stop t reel motor the St p button 25 is device will respond to initiate a controlling acdepressed to Op s C tacts. This will interrupt the coil circuit of line contactor 19 which F a b tt d more complete understanding will open to disconnect reel motor M from the of the invention, reference should now be had to S pp y source 26, and close its o y sed the following specification and to the accompanyinterlock Contacts a to pick up lower coning i t single figure of which is a tactor 24 and automatically return the brushes ple, schematic diagram of an embodiment of the to the position ready for a other Start. When this off" or low speed position is reached, Referring now to the drawing, a pilot-genlimit means including a rider 29 and a switch erator In is shown as being connected t pinch 30 operate to de-energize the contactor 24 and rolls ll between which a length of material l2 thereby the pilot motor '5 passes on t way t th 1 |3 which is driven By means of the adjustable resistance 21 in by a commutator motor M the brushes of which 40 the Coil Circuit of relay he l near speed can are shifted by means of a pilot motor is and be preset to any iven value.

A speed indicating instrument may be con- Depressing the start push tt 5 will close nected across the armature of the tachometerpilot contactor 11 provided the brush gear of the generator In to ve an indication of t e speed commutator reel motor is in the off or low of the materialspeed position and limit switch contacts l8 are With the arrangement described v no in closing seals itself hunting takes place as the speed is being e through contacts '19, and completes the coil ciru ly du ed. cuit of line 'contactor l9 which closes and starts e c ometer-generator can of course be up the reel motor at low speed. The raise driven y any available means which is'pr0D speed button 20 is then depressed to energize and tional to the linear speed of the material and the Close t t 2 which seals itself in through invention is not limited to the method described an interlock 2 la and the bottom contacts 22a of in the pertielllelv ple we have taken.

Contactor 2| in closing will complete The tachometer-generator may be a permanent the energizing circuit for the raise contactor magnet generator or it may have its field sepaof said material produce corresponding voltage variations, electroresponsive means responsive to said voltage variations for energizing said pilot motor to actuate said brush shifting mechanism only to decrease the speed of said brush shifting motor and thereby maintain the speed of said material substantially constant at a predetermined value, switching means for deenergizing said brush shifting motor, and means operated by said switching means when said brush shifting motor is deenergized for energizing said pilot motor independently of said 'electro-responsive device to drive said brush shifting mechanism back to a predetermined low speed setting.

2. The combination with a take-up reel for a strip of material, a drive motor therefor, control means for controlling the speed of the motor in response to the speed of the material, a control element having a low speed position for efiecting low speed operation of the motor and having a plurality of higher speed positions for higher speed operation of the motor, said control means varying the position of said control element only to reduce the speed of said motor thereby to maintain the speed of the material substantially constant, means for stopping the motor, and means operated by said stopping means for returning said control element to said low speed position.

3. The combination with a take-up reel for a strip of material, a drive motor therefor, control means for controlling the speed of the motor in response to the speed of the material, a control element having a low speed position for effecting low speed operation of the motor and having a plurality of higher speed positions for higher speed operation of the motor, means for starting the motor only when said control element is in said low speed position, said control means varying the position of said control element only to reduce the speed of said motor. thereby to maintain the speed of the material substantially constant, means for stopping the motor, and means operated by said stopping means for returning said control element to said low speed position.

4. The combination with a take-up reel for a strip of material, a drive motor therefor, a pilot generator driven at a speed proportional to the speed of the material, control means for said motor including an electro-responsive device responsive to the voltage of said generator, a pilot motor operated by said electro-responsive device and a control element driven by said pilot motor to a plurality of speed positions, said control means being arranged only to decrease the speed of the motor and thereby maintain the speed of the material substantially constant, means for starting the motor only when said control element is in a low speed position, means for stopping the motor, and means including a switch operated by said stopping means for energizing said pilot motor to drive said control element back to said low speed position.

5. The combination with a take-up reel for a strip of material, a drive motor therefor, a pilot generator driven at a speed proportional to the speed of the material, control means for said motor including an electro-responsive device responsive to the voltage of said generator, a pilot motor operated by said electro-responsive device and a control element driven by said pilot motor to a plurality of speed positions, said control means being arranged only to decrease the speed of the motor and thereby maintain the speed of the material substantially constant, means for starting the motor only when said control element is in a low speed position, means for stopping the motor, means including a switch operated by said stopping means for energizing said pilot motor to drive said control element back to said low speed position, and limit means operable by said control element for ole-energizing said pilot motor when said low speed position is reached.

RAYMOND G, RAYDEN. 

